The present invention relates to fuser members useful in electrostatographic reproducing apparatuses, including digital, image on image, and contact electrostatic printing apparatuses. The present fuser members can be used as fuser members, pressure members, transfuse or transfix members, and the like. In an embodiment, the fuser members comprise an outer layer comprising a fluoroelastomer. In embodiments, the fluoroelastomer is selected from the group consisting of a) copolymers of two of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene; b) terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; and c) tetrapolymers of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene and a cure site monomer. In embodiments, the release agent is a fluorosilicone release agent. In embodiments, the fluorosilicone release agent has pendant fluorocarbon groups.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member, and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles and pigment particles, or toner. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support, which may be the photosensitive member itself, or other support sheet such as plain paper.
The use of thermal energy for fixing toner images onto a support member is well known. To fuse electroscopic toner material onto a support surface permanently by heat, it is usually necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This heating causes the toner to flow to some extent into the fibers or pores of the support member. Thereafter, as the toner material cools, solidification of the toner material causes the toner material to be firmly bonded to the support.
Typically, the thermoplastic resin particles are fused to the substrate by heating to a temperature of between about 90xc2x0 C. to about 200xc2x0 C. or higher depending upon the softening range of the particular resin used in the toner. It may be undesirable; however, to increase the temperature of the substrate substantially higher than about 250xc2x0 C. because of the tendency of the substrate to discolor or convert into fire at such elevated temperatures, particularly when the substrate is paper.
Several approaches to thermal fusing of electroscopic toner images have been described. These methods include providing the application of heat and pressure substantially concurrently by various means, a roll pair maintained in pressure contact, a belt member in pressure contact with a roll, a belt member in pressure contact with a heater, and the like. Heat may be applied by heating one or both of the rolls, plate members, or belt members. The fusing of the toner particles takes place when the proper combinations of heat, pressure and contact time are provided. The balancing of these parameters to bring about the fusing of the toner particles is well known in the art, and can be adjusted to suit particular machines or process conditions.
During operation of a fusing system in which heat is applied to cause thermal fusing of the toner particles onto a support, both the toner image and the support are passed through a nip formed between the roll pair, or plate or belt members. The concurrent transfer of heat and the application of pressure in the nip affect the fusing of the toner image onto the support. It is important in the fusing process that no offset of the toner particles from the support to the fuser member takes place during normal operations. Toner particles offset onto the fuser member may subsequently transfer to other parts of the machine or onto the support in subsequent copying cycles, thus increasing the background or interfering with the material being copied there. The referred to xe2x80x9chot offsetxe2x80x9d occurs when the temperature of the toner is increased to a point where the toner particles liquefy and a splitting of the molten toner takes place during the fusing operation with a portion remaining on the fuser member. The hot offset temperature or degradation of the hot offset temperature is a measure of the release property of the fuser roll, and accordingly it is desired to provide a fusing surface, which has a low surface energy to provide the necessary release. To ensure and maintain good release properties of the fuser roll, it has become customary to apply release agents to the fuser roll during the fusing operation. Typically, these materials are applied as thin films of, for example, nonfunctional silicone oils or mercapto- or amino-functional silicone oils, to prevent toner offset.
U.S. Pat. No. 4,257,699 to Lentz, the subject matter of which is hereby incorporated by reference in its entirety, discloses a fuser member comprising at least one outer layer of an elastomer containing a metal-containing filler and use of a polymeric release agent.
U.S. Pat. No. 4,264,181 to Lentz et al., the subject matter of which is hereby incorporated by reference in its entirety, discloses a fuser member having an elastomer surface layer containing metal-containing filler therein and use of a polymeric release agent.
U.S. Pat. No. 4,272,179 to Seanor, the subject matter of which is hereby incorporated by reference in its entirety, discloses a fuser member having an elastomer surface with a metal-containing filler therein and use of a mercapto-functional polyorganosiloxane release agent.
U.S. Pat. No. 5,401,570 to Heeks et al., the subject matter of which is hereby incorporated by reference in its entirety, discloses a fuser member comprised of a substrate and thereover a silicone rubber surface layer containing a filler component, wherein the filler component is reacted with a silicone hydride release oil.
U.S. Pat. No. 4,515,884 to Field et al., the subject matter of which is hereby incorporated by reference in its entirety, discloses a fuser member having a silicone elastomer-fusing surface, which is coated with a toner release agent, which includes an unblended polydimethyl siloxane.
U.S. Pat. No. 5,512,409 to Henry et al. teaches a method of fusing thermoplastic resin toner images to a substrate using amino functional silicone oil over a hydrofluoroelastomer fuser member.
U.S. Pat. No. 5,516,361 to Chow et al. teaches a fusing member having a thermally stable FKM hydrofluoroelastomer surface and having a polyorgano T-type amino functional oil release agent. The oil has predominantly monoamino functionality per active molecule to interact with the hydrofluoroelastomer surface.
U.S. Pat. No. 6,253,055 to Badesha et al. discloses a fuser member coated with a hydride release oil.
U.S. Pat. No. 5,991,590 to Chang et al. discloses a fuser member having a low surface energy release agent outermost layer.
U.S. Pat. No. 6,377,774 B1 to Maul et al. discloses an oil web system.
U.S. Pat. No. 6,197,989 B1 to Furukawa et al. discloses a fluorine-containing organic silicone compound represented by a formula.
U.S. Pat. No. 5,757,214 to Kato et al. discloses a method for forming color images by applying a compound which contains a fluorine atoms and/or silicon atom to the surface of electrophotographic light-sensitive elements.
U.S. Pat. No. 5,716,747 to Uneme et al. discloses a fluororesin coated fixing device with a coating of a fluorine containing silicone oil.
U.S. Pat. No. 5,698,320 to Ebisu et al. discloses a fixing device coated with a fluororesin, and having a fluorosilicone polymer release agent.
U.S. Pat. No. 5,641,603 to Yamazaki et al. discloses a fixing method using a silicone oil coated on the surface of a heat member.
U.S. Pat. No. 5,636,012 to Uneme et al. discloses a fixing device having a fluororesin layer surface, and using a fluorine-containing silicone oil as a repellant oil.
U.S. Pat. No. 5,627,000 to Yamazaki et al. discloses a fixing method having a silicone oil coated on the surface of the heat member, wherein the silicone oil is a fluorine-containing silicone oil and has a specific formula.
U.S. Pat. No. 5,624,780 to Nishimori et al. discloses a fixing member having a fluorine-containing silicone oil coated thereon, wherein the silicone oil has a specific formula.
U.S. Pat. No. 5,568,239 to Furukawa et al. discloses a stainproofing oil for heat fixing, wherein the fluorine-containing oil has a specific formula.
U.S. Pat. No. 5,463,009 to Okada et al. discloses a fluorine-modified silicone compound having a specific formula, wherein the compound can be used for oil-repellancy in cosmetics.
U.S. Pat. No. 4,968,766 to Kendziorski discloses a fluorosilicone polymer for coating compositions for longer bath life.
The use of polymeric release agents having functional groups, which interact with a fuser member to form a thermally stable, renewable self-cleaning layer having good release properties for electroscopic thermoplastic resin toners, is described in U.S. Pat. Nos. 4,029,827; 4,101,686; and 4,185,140, the disclosures each of which are incorporated by reference herein in their entirety. Disclosed in U.S. Pat. No. 4,029,827 is the use of polyorganosiloxanes having mercapto functionality as release agents. U.S. Pat. Nos. 4,101,686 and 4,185,140 are directed to polymeric release agents having functional groups such as carboxy, hydroxy, epoxy, amino, isocyanate, thioether and mercapto groups as release fluids. U.S. Pat. No. 5,716,747 discloses the use of fluorine-containing silicone oils for use on fixing rollers with outermost layers of ethylene tetrafluoride perfluoro alkoxyethylene copolymer, polytetrafluoroethylene and polyfluoroethylenepropylene copolymer. U.S. Pat. No. 5,698,320 discloses the use of fluorosilicone polymers for use on fixing rollers with outermost layers of perfluoroalkoxy and tetrafluoroethylene resins.
Examples of release agents for fuser members are nonfunctional silicone release oils, mercapto-functional silicone release oils, and amino-functional silicone release oils. However, depending on the type of outer layer of the fuser member chosen, there may be several drawbacks to using nonfunctional, mercapto-functional, or amino-functional silicone oils as release agents. For example, for silicone rubber outer layers, the silicone release agents provide adequate wetting of the silicone rubber surface. However, the nonfunctional and functional silicone release agents can swell the silicone rubber coating. Swelling shortens roll life because it weakens the silicone, resulting in rapid mechanical wear. High viscosity (13,000 cS) nonfunctional fluids are currently used with silicone rolls, because these fluids do not swell the rolls as much as lower viscosity (100-350 cS) oils. However, high viscosity oils present fluid management problems and do not wet the fuser as efficiently.
On the other hand, fluoroelastomers used as an outer coating for fuser members are more durable and abrasion resistant than silicone rubber fuser members. Also, fluoroelastomer outer coatings do not swell when contacted by nonfunctional or functional silicone fluids. Therefore, fluoroelastomers are the current desired outer fuser member coating.
With regard to known fusing oils, amino-functional oil has been used with fluoroelastomer fuser member outer layers. However, amino oil does not diffuse into paper products, but instead, reacts with the cellulose in the paper and therefore remains on the surface of the paper. It is believed that hydrogen bonding occurs between the amine groups in the amino oil and the cellulose hydroxy groups of the paper. Alternatively, the amine groups may hydrolyze the cellulose rings in the paper. The amino oil on the surface of the copied paper prevents the binding of glues and adhesives, including the attachable notes such as adhesive of 3-M Post-it(copyright) notes, to the surface of the copied paper. In addition, the amino silicone oil present on the surface of a copied paper prevents ink adhesion to the surface of the paper. This problem results in the poor fix of inks such as bank check endorser inks, and other similar inks.
Yet another drawback to use of amino silicone and silicone fuser release agents is that the release agents do not always react as well with conductive fillers which may be present in the fuser roll surface. It is desirable for the release agent to react with the fillers present on the outer surface of the fuser member in order to lower the surface area of the fillers. The result is that the conductive filler may be highly exposed on the surface of the fuser member, thereby resulting in increased surface energy of the exposed conductive filler, which will cause toner to adhere to it. An increased surface energy, in turn, results in decrease in release, increase in toner offset, and shorter fusing release life.
Another drawback of the use of amino silicone release agents is the high reactivity of amino groups, which facilitates gelation of the polydimethylsiloxane release fluid, and which leads to reaction of the fluid with constituents in the toner. Both of these chemical reactions can cause attachment of toner to the fuser roll surface, and shorten fusing release life.
Therefore, for fluoroelastomeric fuser member outer layers, there exists a specific need for a release agent, which provides sufficient wetting of the fuser member. It is further desired to provide a fuser member release agent, which has little or no interaction with copy substrates such as paper, so that the release agent does not interfere with adhesives and POST-IT(copyright) notes (by 3M) adhering to the copy substrate such as paper. It is further desired that the oil not prevent ink adhesion to the final copy substrate. In addition, it is desired that the release agent does not react with components of the toner nor promote fuser fluid gelation. Also, it is desired to provide a release agent that enables increase in life of the fuser member by improved spreading of the release agent. Another desired property would be to provide a release agent that does not require metal oxide or other anchoring sites on the fuser member surface, thereby reducing safely concerns and lowering fuser member fabrication costs. The elimination of metal oxides is desired, since they catalyze an increased reactivity with fluoroelastomer surfaces toward charge control agents in toner, and thereby shorten roll life. It is also desired to provide a release agent that enhances roll life, and reduces fuser contamination. For fluoroelastomeric fuser member outer layers, it is desired to provide a release agent with fluoro-containing segments. For fluoroelastomeric fuser member outer layers, it is further desired to provide a release agent that is a copolymer of fluoro-containing segments with amine-containing segments by copolymerizing amine-containing silane monomers with fluoro-containing silane monomers, in order to take advantage simultaneously of the excellent spreading properties of the fluoro-fluid and the reactivity of amine towards fluoroelastomer surfaces. Alternatively, in order to enhance wetting characteristics of nonfunctional or functional silicone fluids, a fluoro-fluid can be blended with the nonfunctional or functional fluid.
Embodiments of the present invention include: a fuser member comprising a substrate; an outer layer comprising a fluoroelastomer selected from the group consisting of a) copolymers of two of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; b) terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; and c) tetrapolymers of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, and a cure site monomer; and a release agent material coating on the outer layer, wherein the release agent material coating comprises a fluorinated silicone release agent having the following Formula I: 
wherein m is a number of from about 0 to about 25 and n is a number of from about 1 to about 25; x/(x+y) is from about 1 percent to about 100 percent; R1 and R2 are selected from the group consisting of alkyl, arylalkyl, amino, and alkylamino groups; and R3 is selected from the group consisting of alkyl, arylalkyl, polyorganosiloxane chain, and a fluoro-chain of the formula xe2x80x94(CH2)oxe2x80x94(CF2)pxe2x80x94CF3 wherein o is a number of from about 0 to about 25 and p is a number of from about 1 to about 25.
Embodiments also include: a fuser member comprising a substrate; an outer layer comprising a fluoroelastomer selected from the group consisting of a) copolymers of two of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; b) terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; and c) tetrapolymers of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, and a cure site monomer; and a release agent material coating on the outer layer, wherein the release agent material coating comprises a fluorinated silicone release agent having the following Formula III: 
wherein x/(x+y) is about 7.3 percent.
Embodiments further include: an image forming apparatus for forming images on a recording medium comprising: a charge-retentive surface to receive an electrostatic latent image thereon; a development component to apply a developer material to the charge-retentive surface to develop the electrostatic latent image to form a developed image on the charge retentive surface; a transfer component to transfer the developed image from the charge retentive surface to a copy substrate; and a fuser member component to fuse the transferred developed image to the copy substrate, wherein the fuser member comprises a) a substrate; b) an outer layer comprising a fluoroelastomer selected from the group consisting of i) copolymers of two of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; ii) terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; and iii) tetrapolymers of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, and a cure site monomer; and a release agent material coating on the outer layer, wherein the release agent material coating comprises a fluorinated silicone release agent having the following Formula I: 
wherein m is a number of from about 0 to about 25 and n is a number of from about 1 to about 25; x/(x+y) is from about 1 percent to about 100 percent; R1 and R2 are selected from the group consisting of alkyl, arylalkyl, amino and alkylamino groups; and R3 is selected from the group consisting of alkyl, arylalkyl, polyorganosiloxane chain, and a fluoro-chain of the formula xe2x80x94(CH2)oxe2x80x94(CF2)pxe2x80x94CF3 wherein o is a number of from about 0 to about 25 and p is a number of from about 1 to about 25.